The United States is divided into a plurality of contiguous, non-overlapping exchanges, referred to as Local Access Transport Areas (LATAs), each of which is served by a local telephone company. Telephone calls originating and terminating within the same exchange, referred to as intraLATA calls, are handled end-to-end by a local, intraLATA, telephone company referred to as the Local Exchange Carrier (LEC). Calls originating within one exchange or in a state or foreign country and terminating in a different exchange, potentially in a different state or foreign country, referred to as inter-exchange calls, are handled at each end by the intraLATA company or LEC that services the originating and the terminating exchanges. These inter-exchange calls are carried between the intraLATA companies by one or more inter-exchange carriers, known as long distance carriers.
A caller who wishes to select an inter-exchange carrier other than the default primary inter-exchange carrier (PIC) must dial special access codes that are assigned to each inter-exchange carrier and once connected, must sometimes also dial a personal identification code and the number of the called party to have the call completed. With the proliferation of inter-exchange carriers, carrier selection is often difficult for a telephone communication system user. The user may be unaware of which inter-exchange carrier, available in his/her area, is the most economical for a particular time of day, which inter-exchange carrier serves the user's telephone communication system or what access codes are appropriate for the particular inter-exchange carriers available to the user's telephone communication system.
During the last few years, the competition between telephone companies (also known as operating companies, service providers or carriers) for the telephone subscriber business has increased markedly. This competition is most evident in the multiplicity of tariffs from each carrier, which vary not only between destinations but also according to the nature of the contract signed between the subscriber and the telephone company, the time of day, the length of call and other numerous parameters. In addition, competition exists between intra-exchange service providers.
Though this competition gives the customer an opportunity for saving money, the customer rarely fully benefits because of the complexity and the variety of existing tariffs. For example, tariffs may vary due to the time of day, on weekends, holidays, according to the call destination, distance, method of payment and any time limited promotions. The situation may be further complicated by special limited discounts or other incentives offered by the telephone companies, the entry of new telephone companies to new markets and the grade of service requested (i.e., voice quality, connection delays and first time connection establishment success).
The entry of new money saving services, such as Fax Store and Forward and call-back services, the availability of alternate services offered by private networks using their own PBX and the usage of corporate networks are additional factors affecting the cost of the call. Consequently, the customer has to contend with a huge amount of information in order to determine how to make the least expensive telephone call. Because of the complexity of the charging schemes, a cost optimization on a per call basis is nearly impossible for a subscriber to perform by themselves.
Call management systems are applications suitable not just for large businesses with high call volumes but are also suitable for small office/home office (SOHO) as well. The bewildering array of service providers available and the existence of a complicated tariff structure combine to create a need for a system to manage the placement of telephone calls for SOHO applications.
U.S. Pat. No. 4,791,665 to Bogart et al. describes a telephone communication system (PBX) with the capability of automatically selecting one of a plurality of inter-exchange carriers. The system includes a database containing access code data associated with the inter-exchange carriers, user authorization codes and information about the various inter-exchange carrier billing rates based on time of day and destination. The PBX scans the database and reroutes the originating call to one of the other inter-exchange carriers having a cheaper tariff for the particular destination at the specific time of day. The PBX sends out the inter-exchange carrier access code, the user's personal identification code and the called party number dialed by the user to complete the call.
U.S. Pat. No. 5,425,084 to Brinskele describes a computer controlled telephone communication system which includes a plurality of digital switches each located in different charge zones. Each digital switch is coupled to a file server which determines which of the digital switches to use in order to ensure the lowest possible cost for the call.
U.S. Pat. No. 5,420,914 to Blumhardt describes a real time selection of one of a plurality of inter-exchange carriers which automatically selects the carrier having the least expensive toll at the time the call is made and reroutes the call accordingly. Blumhardt is used in conjunction with an advanced intelligent network (AIN) in a public switched telephone network (PSTN).
U.S. Pat. No. 5,425,085, issued to Weinberger et al., teaches a device that interconnects with the telephone line coming from a first phone and routes telephone calls along a least cost route originating from the first telephone to a second telephone via the network. A database stores billing rate parameters for determining various communications paths of different carriers based on parameters such as the time and date of the call.
U.S. Pat. No. 5,519,769, issued to Weinberger et al., teaches a system for updating a database which stores billing rate parameters for call rating devices associated with a calling station. At predetermined times the calling station calls a rate provider which provides billing rate data parameters for a plurality of calling stations.
U.S. Pat. No. 5,473,630, issued to Penzias et al., teaches a method of accessing long distance rate information available in a database provided by inter-change carriers. PBXs and telephone central offices access that rate information using ISDN and/or SS7 signaling and use it as a basis for determining which carrier to use at any given time in the routing of a call.
In prior art call management systems, updating the tariff database is very complicated since the interface to do so is cumbersome and a huge amount of complex data is involved. Therefore, the operators of the call management system rarely update their tariff databases. As a result, the routing decision taken may not necessarily be the optimum route for the call, at that time.